Four vane elliptical rotary air conditioning compressor

ABSTRACT

A rotary hermetically sealed refrigerant electric compressor having an elliptically shaped compression chamber in which a symmetrical rotating rotor, keyed on the drive shaft in an axially slidable manner, includes opposed pairs of sliding vanes providing an inherently balanced bearing loading. The shear forces caused by the compressor rotor revolving against the lower bearing plate are reduced by incorporating a thrust element between the electric motor rotor and stationary hub portion of the upper bearing plate allowing limited movement of the compressor rotor on the shaft in an axial direction to provide for out of squareness dimensional tolerances between the compressor rotor, the shaft and the compression chamber.

0 United States Patent 1 [111 3,790,311 Butts et a]. Feb. 5, 1974 [54] FOUR VANE ELLIPTICAL ROTARY AIR 3,003,682 10/1961 Tarleton 417/410 CO DI COMPRESSOR 3,097,610 7/1963 Swanson 418/182 [75] Inventors: Mervin-R. Butts, West Milton; P E C J H Joseph J. Robbins, West Alexandria,' nmary xammer usar both of Ohio Attorney, Agent, or Fzrm--Edward P. Barthel 73 Assi nee: General Motors Cor ration 1 g Detroit, Mich. [57] ABSTRACT [22] Filed Nov 27 1972 A rotary hermetically sealed refrigerant electric compressor having an elliptically shaped compression [21] Appl. No.: 309,789 chamber in which a symmetrical rotating rotor, keyed on the drive shaft in an axially slidable manner, in cludes opposed pairs, of sliding vanes providing an in- [52] us Cl 417/410 47 6 3 0 herently balanced bearing loading. The shear forces 51 Int. Cl F64b 17/00 caused by the cmpressr ewlving against the 58 Field of Search.... 417/410 424- 418/209 182 beanng Plate are reduced by incmpmmg a 418/266 thrust element between the electric motor rotor and stationary hub portion of the upper bearing plate al- [56] References Cited lowing limited movement of the compressor rotor on the shaft in an axial direction to provide for out of UNITED STATES PATENTS squareness dimensional tolerances between the comsl gf e! 417/41O pressor rotor, the shaft and the compression chamber. lie

4/1953 Clerc 418/182 3 Claims, 4 Drawing Figures PAIENIEDFEB 51914 3390.311

' SHEEI i [If 2 PAIENTEBFEB W- 3,790.31. 1

sum 2 BF 2 FOUR VANE ELLIPTICAL ROTARY AIR CONDITIONING COMPRESSOR This invention relates to a rotating vane refrigerant gas compressor and more particularly to a hermetically sealed compressor having an elliptically shaped compression chamber providing inherently balanced bearing loadings.

One problem in designing a rotary compressor for use in a refrigerating systemwherein pairs of sliding vanes are provided on a symmetrically positioned rotor is to reduce the shear forces which result from the rotor revolving against the lower bearing plate under an applied thrust load. Another problem results from the squareness requirements between the driving shaft and the rotor.

It is an object of this invention to provide an improved construction for a refrigerant gas compressor having an elliptically shaped cylinder in which a symmetrically positioned rotor incorporating opposed pairs of sliding vanes, is mounted for axial movement on the motor shaft in a manner whereby the rotor is free to float on the motor shaft by providing axial thrust means between the motor rotor and the upwardly extendingfixed hub portion of the upper bearing plate.

It is another object of the invention to provide a gas intake manifold arrangement for a refrigerant gas compressor having an elliptically shaped cylinder wherein the refrigerant gas is supplied to the working chamber from both the upper and lower bearing plates.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIG. 1 is a diametric section of a compressor provided with an elliptical chamber taken on line 1-1 of FIG. 2;

FIG. 2 is a horizontal sectional view taken along line 2-2 of FIG.,1

FIG. 3 is a horizontal sectional view taken along line 3-3 of FIG. 1; and,

FIG. 4 is a fragmentary horizontal section along the line 4-4 of FIG. 1.

' Referring now to the drawings wherein a preferred embodiment of the invention has been shown, reference numeral designates an inverted cup-shaped sheet metal housing element which serves to enclose the motor compressor assembly, generally designated taken by the reference numeral 12. The motor compressor assembly includes a cast frame upper bearing plate 14 which is encased in a press fitted manner within the casing 10. A closure plate 18 is welded or otherwise secured to the housing bottom edge to hermetically seal the open end of the housing 10. An electric motor stator 20 having windings 21 is fixedly encased in the housing and a complementary motor revolving rotor 22 is supported on the upper end of the main compressor drive shaft 24 in a substantially integrally fitted manner. The drive shaft 24 is provided with an intermediate polygonal shaped portion 25, preferably having a square cross section (FIG. 4), for reception within a complementary shape aperture 27 in compressor slotted rotor member 28 so as to be keyed thereon such that the slotted circular rotor 28 is symmetrically disposed in elliptical shaped compression chamber 30 for rotation therein. The compressor structure includes the upper bearing plate or head 14, a chamber or cylinder forming plate 32 and a lower bearing plate or head 34 including a cover-plate 35 maintained in assembled relationship by suitable means such as bolts 36. A small diameter end portion 26 on the lower end of the shaft is joumalled in a bearing 29 in the lower plate 34.

The lower portion of the housing 10 serves as a lubricant reservoir from whence oil for lubricating the shaft journal bearings is withdrawn by means of an oil pickup helical blade located in the downwardly opening bore 42 communicating with a reduced vertical passage 44 overlying the bore 42. As the shaft 24 rotates at a high speed the lubricating oil is drawn upwardly through the bore 42 and passageway 44 and thrown out to horizontal passages 46 and 48. The lubricating oil passes through the radial passageways 46 and 48 into a spiral groove 50in the periphery of the shaft 24 which extends upwardly in the hub portion 52 of upper bearing plate 14 such that the lubricating oil is urged upwardly in the groove 50 by centrifugal force and spills onto the top of the hub 52 and flows downwardly therefrom.

A thrust washer 54 encircles the shaft 24 between the upper surface 56 of the hub 52 and the lower thrust bearing surface 58 on the rotor 22 operating respectively on the lower and upper opposite faces of the thrust washer for preventing downward axial movement of the motor rotor 22 and drive shaft 24 in a manner whereby the thrust washer 54 receives the main axial thrust loading taken against the lower bearing plate 34.

As seen in FIG. 3, the compression chamber 30 is of elliptical configuration in which is located the symmetrical rotating compressor rotor 28 provided with two pair of diametrically opposed radially outwardly opening slots 71, 72, 73 and 74 in which vanes or blades 76, 77, 78 and 79 respectively, are slidably received. In the illustrated embodiment of the invention, the ends of the blades are biased against the elliptical walls of the compression chamber by means of helical compression springs 75 in the rear circular part of the radial slots. In this manner the spring loaded vanes are located such that the vanes 76 and 78 are oriented 180 apart to remain in contact with the elliptical chamber surface while in the same manner the vanes 77 and 79 are also oriented 180 apart. The diametrically opposed pairs of vanes provide four simultaneous compression strokes with resultant opposite and equal forces balanced bearing to theoretically cancel out joumalled bearing loads on the shaft 24 due to the compression of the refrigerant gas in the chamber 30.

As seen in FIG. 3,the compressor is provided with an inlet 80 in the housing wall in a manner similar to the outlet 81 in accordance with the usual practice. The inlet 80 communicates by means of a common vertical inlet passage 82 with a pair of superimposed composite arcuate channels 86, 87, as seen in FIG. 1 for channel 87, formed by groove 87a in the under surface of the upper bearing plate 14 and the groove 87b in the upper surface of cylinder 32. In a manner shown by the arrows in FIG. 3, the gas is split between the channels 86 and 87, and moves into. duplicate diametrically opposed manifold arcuate openings 90 and 91 formed in cylinder 32 whereby the gas from each opening 90, 91 is fed to duplicate axially aligned compression chamber delivery ports 92, 93 and 94, 95 respectively.

As viewed in FIG. 2, the lower delivery ports 92 and 94 are formed in the top surface of lower bearing plate 34 while the upper delivery ports 93 and 95 are formed in the bottom surface of the upper bearing plate 32 such that the opposed working chambers 30a and 30b are fed simultaneously from both the top and bottom bearing plates during a portion of a cycle of the rotor 28 from their associated delivery ports while during another portion of the same cycle of the rotor 28 the working chambers 30c and 30d are fed simultaneously from both sides by their associated delivery ports, thereby providing smooth flow of the refrigerant gas and reduced pressure drop.

As the rotor 28 rotates in a counterclockwise direction, as viewed in FIG. 3, gas is drawn into the suction inlet 80 and down the vertical inlet passageway 82, the arcuate grooves 86 and 87, the openings 90 and 91 and will fill up the low pressure chambers 30a and 30b. As the rotor 28 rotates the gases within the high pressure sides 30c and 30d are forced out opposed bevel grooves 96, 97 in the edge of the cylinder 32 into the direction of the discharge ports 98 (FIG. 1) of opposed valve means 100, 102 and are compressed within the decreasing volume bounded by the blades, the rotor and the elliptical wall of the compression chamber. As seen in FIG. 1 the valve means 100, 102 are check valves and include an outer coil spring 104 which is held in place by a stamping 106 whereby spring pressure is applied continuously to the valve discharge disc 108 for biasing it toward the closed position.

The gas which flows past the disc is directed into vertical exit passageways 110, '112 into lobed groove 116 formed on the inner face of the lower bearing plate. As seen in FIG. 2 the compressed gas flows in the direction of the arrows from opposed lobes 118, 120 into the circular groove 116 to enter the common lobe 122 and out the vertical common exit passage l24to the outlet port 81. It will be noted that valve means 100 may be provided with a second concentric inner coil spring 132 for biasing valve plate 134 to provide a relief valve outlet to prevent excessive pressure within the chamber 30.

A feature of applicants invention involves the keylike mounting arrangement of slotted rotor 28 on the polygonal section of the shaft 24. As seen in FIG. 4 the intermediate shaft portion 25 is formed with a generally square cross section to allow for sliding reception thereon of the conforming square aperture 27 in the slotted rotor. By virtue of thislimited free-floating arrangement, in counter-distinction to an integral rotor and shaft, the'rotor 28 is free to float or move axially on the square-sectioned intermediate portion 25 of the shaft with sufficient dimensional allowance so as to accommodate for any out-of-squareness of tolerance build-up between the compressor rotor 28, the shaft 24 and the wall surfaces of the compression chamber 30. The shear or frictional torque forces which normally result from the compressor rotor'28 moving against the compresssion chamber horizontal lower wall surface formed by the bearing plate 34 with an applied thrust load are significantly reduced by incorporating a thrust element in the form of the thrust washer 54 between the motor rotor 22 and upper surface 56 of the hub portion 52. It will be noted that the axial length of the intermediate square sectionedshaft portion 25 has a predetermined axial dimension greater than the thickness of the rotor 28 to insure full keyed alignment between the compression rotor and the shaft.

While the embodiment of the present invention as herein disclosed constitutes'a preferred form, it is to be understood that other forms might be adopted.

We claim:

1. In a refrigerant compressor, the combination of, a hermetically sealed casing; a motor including a motor rotor, stator and vertically disposed shaft having its upper portion fixedly secured to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, acylinder forming plate and a lower bearing plate; said shaft rotatably received within said upper bearing plate; said cylinder forming plate having an elliptical shaped compressor chamber; a circular shaped slotted rotor rotatably symmetrically positioned in said compressor chamber, and having a plurality of paired diametrically opposed vane slots thereon, vanes slidably received in said slots being outwardly biased into engagement with the elliptical wall of said compression chamber; a reduced small diameter bearing portion on the lower end of said shaft rotatably received within said lower bearing plate; an intermediate polygonal sided portion on said shaft extending through said compression chamber slidably received within a complementary polygonalsided aperture in said slotted rotor, whereby said slotted rotor is free to move a predetermined amount in a vertical direction on said shaft intermediate portion so as to provide for any out of squareness tolerances between said slotted rotor and said compression chamber, said upper bearing plate having a hub portion extending upwardly to a point adjacent said motor rotors bottom surface, a thrust element positioned on said shaft between the upper end surface of said hub and said motor rotors bottom surface to receive the axial thrust loading of said motor rotor on said upper bearing plate thereby reducing frictional torque forces between said slotted rotor and said lower bearing plate.

. 2. In a refrigerant compressor, the combination of, a hermetically sealed casing; a motor including a motor rotor, stator and vertically disposed shaft having its upper portion fixedly secured to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, a cylinder plate and a lower bearing plate; said shaft rotatably received within said upper bearing plates; said cylinder plate having an elliptical shaped compressor chamber formed therein; a circular shaped slotted rotor rotatably symmetrically positioned in said compressor chamber, and having two pairs of diametrically opposed ninety degree spaced vane slots therein, vanesslidably received in said slots being outwardly biased into engagement 'with the elliptical wall of said compression chamber; a small diameter bearing portion on the lowerend of said shaft rotatably received within said lower bearing plate; an intermediate square cross section portion on said shaft extending through said compression chamber having a square cross section slidably received within a complementary square shaped aperture in said slotted rotor, the axial length of said intermediate portion being a predetermined amount greater than the thickness of said slotted rotor whereby said slotted rotor is free to move a predetermined amount in a vertical direction on said shaft intermediate portion so as to accommodate out of squareness dimensional tolerances between said slotted rotor,

said shaft and said compression chamber lower wall surface, said upper bearing plate having an integral hub portion extending upwardly to a point adjacent said motor rotors bottom surface, a thrust washer positioned on said shaft between the upper end surface of 5 said hub and said motor rotors bottom surface dimensional to receive the axial thrust loading of said motor rotor on said upper bearing plate thereby reducing frictional torque forces between said slotted rotor and the top horizontal wall surface of said lower bearing plate.

3. In a refrigerant compressor, the combination of; a hermetically sealed casing, a motor including a motor rotor, stator and a vertically disposed shaft having its upper portion fixedly secured to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, a cylinder plate and a lower bearing plate; said shaft rotatably received within said upper bearing plate, said cylinder plate having an elliptical shaped compression chamber formed therein, a circular shaped slotted rotor rotatably symmetrically positioned in said compression chamber, and having two pairs of diametrically opposed ninety degree spaced vane slots therein, vanes slidably received in said slots being outwardly biased into engagement with the elliptical wall of said compression chamber thereby forming opposed working chambers within said elliptical compression chamber, a bearing portion on the lower end of said shaft rotatably received within said lower bearing plate, means for retaining said rotor on an intermediate portion of said shaft so as to be rotatable therewith while allowing limited axial movement thereon between said bearing plates, refrigerant vapor inlet means in said compressor, said inlet means including a common vertical inlet passage in said upper bearing plate, arcuate grooves formed in the under surface of said upper bearing plate and the upper surface of said cylinder plate, said arcuate grooves being superimposed to provide two symmetrical arcuate channels each communicating with said vertical inlet passage, said cylinder plate having diametrically opposed arcuate shaped manifold opening extending therethrough such that each communicates with the distal end of one of said channels, two pairs of axially aligned upper and lower compression chamber delivery ports, said lower delivery ports formed in the top surface of said lower bearing plate and said upper delivery ports formed in the bottom surface of said upper bearing plate, said lower delivery ports and said upper delivery ports respectively being in diametrically opposed relation, each of said delivery ports extending radially so as to partially overlie in symmetrical fashion in associated manifold opening and a portion of said elliptical compression chamber such that the opposed working chambers formed by said elliptical compression chamber and said vanes are fed with refrigerant vapor from both the upper and lower bearing plates.

zg gg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,790,311 batediebruary 5', 1974 Inventor(s) Mervin R. Butts et all,

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

i Column 1, line 63, "shape" should read shaped j .Column 3, line 55, before "tolerance" change "0;?" to or column 4, line 42, before "vertically" insert a lines 57 and 58, delete square cross section". Column 6, line 22, after "fashion" change "in" to an Signed and sealed this 10th day of' September 1971+.

(SEAL) Attest: I

MCCOY M. GIBSON, JR. c. MARSHALL DANN Att'esting Officer o. 7 Commissioner of Patents 

1. In a refrigerant compressor, the combination of, a hermetically sealed casing; a motor including a motor rotor, stator and vertically disposed shaft having its upper portion fixedly securEd to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, a cylinder forming plate and a lower bearing plate; said shaft rotatably received within said upper bearing plate; said cylinder forming plate having an elliptical shaped compressor chamber; a circular shaped slotted rotor rotatably symmetrically positioned in said compressor chamber, and having a plurality of paired diametrically opposed vane slots thereon, vanes slidably received in said slots being outwardly biased into engagement with the elliptical wall of said compression chamber; a reduced small diameter bearing portion on the lower end of said shaft rotatably received within said lower bearing plate; an intermediate polygonal sided portion on said shaft extending through said compression chamber slidably received within a complementary polygonal sided aperture in said slotted rotor, whereby said slotted rotor is free to move a predetermined amount in a vertical direction on said shaft intermediate portion so as to provide for any out of squareness tolerances between said slotted rotor and said compression chamber, said upper bearing plate having a hub portion extending upwardly to a point adjacent said motor rotor''s bottom surface, a thrust element positioned on said shaft between the upper end surface of said hub and said motor rotor''s bottom surface to receive the axial thrust loading of said motor rotor on said upper bearing plate thereby reducing frictional torque forces between said slotted rotor and said lower bearing plate.
 2. In a refrigerant compressor, the combination of, a hermetically sealed casing; a motor including a motor rotor, stator and vertically disposed shaft having its upper portion fixedly secured to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, a cylinder plate and a lower bearing plate; said shaft rotatably received within said upper bearing plates; said cylinder plate having an elliptical shaped compressor chamber formed therein; a circular shaped slotted rotor rotatably symmetrically positioned in said compressor chamber, and having two pairs of diametrically opposed ninety degree spaced vane slots therein, vanes slidably received in said slots being outwardly biased into engagement with the elliptical wall of said compression chamber; a small diameter bearing portion on the lower end of said shaft rotatably received within said lower bearing plate; an intermediate square cross section portion on said shaft extending through said compression chamber having a square cross section slidably received within a complementary square shaped aperture in said slotted rotor, the axial length of said intermediate portion being a predetermined amount greater than the thickness of said slotted rotor whereby said slotted rotor is free to move a predetermined amount in a vertical direction on said shaft intermediate portion so as to accommodate out of squareness dimensional tolerances between said slotted rotor, said shaft and said compression chamber lower wall surface, said upper bearing plate having an integral hub portion extending upwardly to a point adjacent said motor rotor''s bottom surface, a thrust washer positioned on said shaft between the upper end surface of said hub and said motor rotor''s bottom surface dimensional to receive the axial thrust loading of said motor rotor on said upper bearing plate thereby reducing frictional torque forces between said slotted rotor and the top horizontal wall surface of said lower bearing plate.
 3. In a refrigerant compressor, the combination of; a hermetically sealed casing, a motor including a motor rotor, stator and a vertically disposed shaft having its upper portion fixedly secured to said motor rotor; a compressor located below said motor; said compressor including an upper bearing plate, a cylinder plate and a lower bearing plate; said shaft rotatably received within said upper bearing plate, said cylinder plate havinG an elliptical shaped compression chamber formed therein, a circular shaped slotted rotor rotatably symmetrically positioned in said compression chamber, and having two pairs of diametrically opposed ninety degree spaced vane slots therein, vanes slidably received in said slots being outwardly biased into engagement with the elliptical wall of said compression chamber thereby forming opposed working chambers within said elliptical compression chamber, a bearing portion on the lower end of said shaft rotatably received within said lower bearing plate, means for retaining said rotor on an intermediate portion of said shaft so as to be rotatable therewith while allowing limited axial movement thereon between said bearing plates, refrigerant vapor inlet means in said compressor, said inlet means including a common vertical inlet passage in said upper bearing plate, arcuate grooves formed in the under surface of said upper bearing plate and the upper surface of said cylinder plate, said arcuate grooves being superimposed to provide two symmetrical arcuate channels each communicating with said vertical inlet passage, said cylinder plate having diametrically opposed arcuate shaped manifold opening extending therethrough such that each communicates with the distal end of one of said channels, two pairs of axially aligned upper and lower compression chamber delivery ports, said lower delivery ports formed in the top surface of said lower bearing plate and said upper delivery ports formed in the bottom surface of said upper bearing plate, said lower delivery ports and said upper delivery ports respectively being in diametrically opposed relation, each of said delivery ports extending radially so as to partially overlie in symmetrical fashion in associated manifold opening and a portion of said elliptical compression chamber such that the opposed working chambers formed by said elliptical compression chamber and said vanes are fed with refrigerant vapor from both the upper and lower bearing plates. 